.NET Trick Question

What do you think will be the output of the following code:

    class Program

    {

        public class StringClass

        {

            public string TheString { get; set; }

        }

        static void Main(string[] args)

        {

            List<StringClass> stringClassList = new List<StringClass>(){

                new StringClass{TheString="asdf"}

            };

            IEnumerable<StringClass> stringClassEnumerable = stringClassList;

            IEnumerable<StringClass> AllItems = stringClassEnumerable.Where(item => (true));

            stringClassList.Add(new StringClass { TheString = "fdsa" });

            foreach (StringClass item in AllItems)

            {

                Console.WriteLine(item.TheString);

            }

            Console.ReadKey();

        }

    }

If you think the output is :
asdf

You are wrong.
It is :
asdf
fdsa

This is because the result from the where extension methods is deferred till you try to access the result (in this case the foreach loop).

Enjoy!